Back frame and backlight system of flat panel display device

ABSTRACT

The present invention provides a back frame of a flat panel display device. The back frame includes at least two assembling pieces. The at least two assembling pieces are joined to form the back frame. The back frame further includes a bracing piece that is set in pawl mating engagement with the assembling pieces. The present invention further provides a backlight system. The back frame and backlight system of flat panel display device form a back frame through joining assembling pieces so that the structure of a mold for back frame is simple, the expenditure for the back frame mold is reduced, the material for the back frame is saved, and the cost of flat panel display device is lowered down. Further, through the pawl mating arrangement of the bracing piece and the assembling piece, the bracing piece of the back frame realizes fast mounting and removal.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of displaying techniques, andin particular to a back frame and a backlight system of a flat paneldisplay device.

2. The Related Arts

The state-of-the-art liquid crystal display device comprises a frontbezel, a panel, and a backlight module, of which the backlight modulecomprises a back frame, a reflector plate, a light guide, and a lightingassembly.

Currently, a variety of display panels of different sizes are availablein the market to meet different needs of general consumers. For example,in the field of television set, the sizes of liquid crystal panelsinclude 31.5, 42, 46, 48, and 55 inches. Different back frame molds areprovided for liquid crystal planes of different sizes.

Referring to FIG. 1, FIG. 1 is a schematic view showing a conventionalback frame of liquid crystal display device. As shown in FIG. 1, theconventional back frame 10 is a unitary back frame, and it is often thata unitary back frame 10 is made with metal stamping or plastic injectionmolding. The unitary back frame 10 consumes much material and has a highmaterial cost. Further, a large-sized back frame 10 requires large-sizedstamping equipment, and the size of mold corresponding to such a backframe 10 is large and the structure complicated, making the expenditureof the back frame mold high. As a consequence, the conventional backframe is of a high cost.

SUMMARY OF THE INVENTION

The technical issue to be addressed by the present invention is toprovide a back frame and a backlight system of a flat panel displaydevice, which save material for the back frame, reduce the cost, andallow a bracing piece of the back frame to realize fast mounting andremoval.

To address the above technical issue, the present invention adopts atechnical solution that provides a back frame of flat panel displaydevice. The back frame comprises at least two assembling pieces, the atleast two assembling pieces being joined to form the back frame, theback frame further comprising a bracing piece, the bracing piece beingset in pawl mating engagement with the assembling pieces.

According to a preferred embodiment of the present invention, thebracing piece forms pawls thereon and the assembling pieces formengagement sites for receiving the pawls.

According to a preferred embodiment of the present invention, the backframe comprises at least two primary assembling pieces, the at least twoprimary assembling pieces being joined to form a main frame structure ofthe back frame, the at least two primary assembling pieces comprising afirst primary assembling piece and a second primary assembling piece,the first primary assembling piece having an end forming at least twojoint sections, each of the joint sections having a structure mating anend of the second primary assembling piece, the first primary assemblingpiece using one of the joint sections to join the corresponding end ofthe second primary assembling piece.

According to a preferred embodiment of the present invention, the atleast two joint sections are arranged to space from each other in alengthwise direction of the first primary assembling piece.

According to a preferred embodiment of the present invention, the jointsections comprise recesses formed in a surface of the first primaryassembling piece and having a shape corresponding to the end of thesecond primary assembling piece for receiving the end of the secondprimary assembling piece.

According to a preferred embodiment of the present invention, the jointsections comprise recesses formed in a surface of the first primaryassembling piece, the second primary assembling piece having a surfaceforming protrusions at corresponding positions, the protrusions beingreceivable in the recesses to join the first primary assembling pieceand the second primary assembling piece to each other.

According to a preferred embodiment of the present invention, the secondprimary assembling piece has an end having a surface forming at leasttwo protrusions that are arranged to space from each other in alengthwise direction of the second primary assembling piece.

According to a preferred embodiment of the present invention, therecesses comprise polygonal recesses and the protrusions are shaped ascorresponding polygonal protrusions.

According to a preferred embodiment of the present invention, the recessof the first primary assembling piece forms in a bottom thereof a firstthrough hole, the second primary assembling piece forming in acorresponding location a second through hole, the back frame comprisinga fastener, the fastener extending through the first through hole andthe second through hole to join the first primary assembling piece andthe second primary assembling piece to each other.

To address the above technical issue, the present invention adopts atechnical solution that provides a backlight system. The backlightsystem comprises a light source, a light homogenization mechanism, and aback frame; and the back frame carries the light source and the lighthomogenization mechanism. The back frame is a back frame of the backframe described in the above embodiments.

The efficacy of the present invention is that to be distinguished fromthe state of the art, the present invention provides a back frame and abacklight system that form a back frame through joining assemblingpieces so that the structure of a mold for back frame is simple, theexpenditure for the back frame mold is reduced, the material for theback frame is saved, and the cost of flat panel display device islowered down. Further, through the pawl mating arrangement of thebracing piece and the assembling piece, the bracing piece of the backframe realizes fast mounting and removal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing a conventional back frame of liquidcrystal display device;

FIG. 2 is a schematic view showing a flat panel display device accordingto a first embodiment of the present invention;

FIG. 3 is a schematic view showing a back frame of a flat panel displaydevice according to a second embodiment of the present invention;

FIG. 4 is a schematic view showing a back frame of a flat panel displaydevice according to a third embodiment of the present invention;

FIG. 5 is a schematic view showing a back frame of a flat panel displaydevice according to a fourth embodiment of the present invention;

FIG. 6 is a schematic view showing a joining structure of a flat paneldisplay device according to a fifth embodiment of the present invention;

FIG. 7 is a schematic view showing a diagonally-arranged first secondaryassembling piece mounted to a main frame structure of a flat paneldisplay device according to a sixth embodiment of the present invention;

FIG. 8 is a schematic view showing a first secondary assembling pieceand a second secondary assembling piece mounted to a main framestructure of a flat panel display device according to a seventhembodiment of the present invention;

FIG. 9 is a schematic view showing joint sections of a back frame of aflat panel display device according to an eighth embodiment of thepresent invention;

FIG. 10 is a cross-sectional view showing a first example of jointsection of FIG. 9;

FIG. 11 is a schematic view showing a joining structure of a jointsection of a back frame of a flat panel display device according to aninth embodiment of the present invention;

FIG. 12 is a schematic view showing a joining structure of a jointsection of a back frame of a flat panel display device according to atenth embodiment of the present invention;

FIG. 13 is a schematic view showing a joining structure of a jointsection of a back frame of a flat panel display device according to aneleventh embodiment of the present invention;

FIG. 14 is a schematic view showing a joint section of a back frame of aflat panel display device according to a twelfth embodiment of thepresent invention;

FIG. 15 is a schematic view showing a joint section of a back frame of aflat panel display device according to a thirteenth embodiment of thepresent invention;

FIG. 16 is a flow chart showing a method for manufacturing a back frameof a flat panel display device according to a fourteenth embodiment ofthe present invention;

FIG. 17 is a schematic view showing a flat panel display device with atouch screen according to a fifteenth embodiment of the presentinvention;

FIG. 18 is a schematic view showing a stereoscopic display deviceaccording to a sixteenth embodiment of the present invention;

FIG. 19 is a schematic view showing a plasma display device according toa seventeenth embodiment of the present invention;

FIG. 20 is a cross-sectional view showing pawl mating engagement of abracing piece and assembling pieces according to an eighteenthembodiment of the present invention; and

FIG. 21 is a cross-sectional view showing pawl mating engagement of abracing piece and assembling pieces according to a nineteenth embodimentof the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 2-3, FIG. 2 is a schematic view showing a flat paneldisplay device according to a first embodiment of the present inventionand FIG. 3 is a schematic view showing a back frame of a flat paneldisplay device according to a second embodiment of the presentinvention. As shown in FIG. 2, the flat panel display device 20according to the instant embodiment comprises: a backlight system 21 anda display panel 22. The backlight system 21 is arranged on a back sideof the display panel 22 and supplies light to the display panel 22.

In the instant embodiment, the backlight system 21 comprises a lightsource 25, a light homogenization mechanism 24, and a back frame 23. Theback frame 23 carries the light source 25 and the light homogenizationmechanism 24. When the backlight system 21 is an edge lighting type, thelight homogenization mechanism 24 is a light guide; and when thebacklight system 21 is a direct type, the light homogenization mechanism24 is a diffuser plate. The back frame 23 comprises at least a firstprimary assembling piece and a second primary assembling piece, and thetwo of at least a first and second primary assembling pieces constitutea main frame structure 27 of the back frame 23.

Referring also to FIG. 3, the back frame 23 of the first embodimentcomprises a first primary assembling piece 261 and a second primaryassembling piece 262. The first primary assembling piece 261 has an endjoined to an end of the second primary assembling piece 262, and thefirst primary assembling piece 261 has another end joined to another endof the second primary assembling piece 262 in order to form the mainframe structure 27 of the back frame 23. The first primary assemblingpiece 261 and the second primary assembling piece 262 are both aluminumpieces or galvanized steel pieces. In the instant embodiment, the firstprimary assembling piece 261 and the second primary assembling piece 262are L-shaped.

Referring also to FIG. 4, the back frame 23 of a second embodimentcomprises a first primary assembling piece 281, a second primaryassembling piece 282, and a third primary assembling piece 283. Thethree primary assembling pieces 281, 282, and 283 are assembled andjoined to form a main frame structure 27 of the back frame 23. The threeprimary assembling pieces 281, 282, and 283 are all aluminum pieces orgalvanized steel pieces. In the instant embodiment, the first primaryassembling piece 281 is L-shaped, and the second and third primaryassembling pieces 282, 283 are straight linear.

Further, the back frame 23 further comprises secondary assembling piecesarranged inside and joined to the main frame structure 27.

A detailed description will be given to the back frame 23 of the flatpanel display device 20 according to the present invention, whichcomprises four primary assembling pieces and two secondary assemblingpieces.

Referring to FIG. 5, FIG. 5 is a schematic view showing a back frame offlat panel display device according to a fourth embodiment of thepresent invention. As shown in FIG. 5, in the instant embodiment, a backframe 23 comprises: a first primary assembling piece 231, a secondprimary assembling piece 232, a third primary assembling piece 233, afourth primary assembling piece 234, a first secondary assembling piece235, a second secondary assembling piece 236, and bracing pieces 2371,2372, 2373, 2374, 2375, 2376, and 2377. The first primary assemblingpiece 231, the second primary assembling piece 232, the third primaryassembling piece 233, and the fourth primary assembling piece 234 aresuccessively joined to each other in an end-to-end manner to constitutea rectangular main frame structure 27 of the back frame 23. The firstsecondary assembling piece 235 and the second secondary assembling piece236, serving as ancillary assembling pieces, are arranged in the mainframe structure 27 and joined to the main frame structure 27.

Specifically, an end of the first primary assembling piece 231 is joinedto an end of the second primary assembling piece 232, another end of thesecond primary assembling piece 232 is joined to an end of the thirdprimary assembling piece 233, another end of the third primaryassembling piece 233 is joined to an end of the fourth primaryassembling piece 234, and another end of the fourth primary assemblingpiece 234 is joined to another end of the first primary assembling piece231 in order to form the rectangular main frame structure 27. The firstprimary assembling piece 231, the second primary assembling piece 232,the third primary assembling piece 233, and the fourth primaryassembling piece 234 are all aluminum pieces or galvanized steel pieces.In the instant embodiment, the first primary assembling piece 231, thesecond primary assembling piece 232, the third primary assembling piece233, and the fourth primary assembling piece 234 are straight linear,yet in other embodiments, it is apparent to those skilled in the art tomake all the first primary assembling piece 231, the second primaryassembling piece 232, the third primary assembling piece 233, and thefourth primary assembling piece 234 L-shaped, or some being straightlinear and the remaining being L-shaped. For example, in FIG. 3, thefirst primary assembling piece 261 and the second primary assemblingpiece 262 are both L-shaped; in FIG. 4, the first primary assemblingpiece 281 is L-shaped, while the second and third primary assemblingpieces 282 and 283 are straight linear.

In the instant embodiment, the back frame 23 of the flat panel displaydevice 20 is formed by joining connection. As shown in FIG. 6, anillustrative example is given for the connection of an end of the firstprimary assembling piece 231 to an end of the second primary assemblingpiece 232, wherein the end of the second primary assembling piece 232 isjoined to the end of the first primary assembling piece 231 by means offor example screwing, fastening, or welding, to have the end of thesecond primary assembling piece 232 connected to the end of the firstprimary assembling piece 231.

In the instant embodiment, the first secondary assembling piece 235 andthe second secondary assembling piece 236 are arranged in the main framestructure 27 of the back frame 23. An end of the first secondaryassembling piece 235 is joined to the first primary assembling piece 231and another end of the first secondary assembling piece 235 is joined tothe third primary assembling piece 233; and an end of the secondsecondary assembling piece 236 is joined to the first primary assemblingpiece 231 and another end of the second secondary assembling piece 236is joined to the third primary assembling piece 233. Further, the secondprimary assembling piece 232, the fourth primary assembling piece 234,the first secondary assembling piece 235, and the second secondaryassembling piece 236 are arranged parallel to each other. In otherembodiments, those skilled in the art may arrange at least one secondaryassembling piece in the main frame structure 27. For example, only thefirst secondary assembling piece 235 is arranged in the main framestructure 27. Further, the two ends of the first secondary assemblingpiece 235 can be selectively joined to at least two of the primaryassembling pieces of the first primary assembling piece 231, the secondprimary assembling piece 232, the third primary assembling piece 233,and the fourth primary assembling piece 234. For example, the firstsecondary assembling piece 235 is set diagonally in the main framestructure 27, as shown in FIG. 7. Similarly, the two ends of the secondsecondary assembling piece 236 can be selectively joined to at least twoof the primary assembling pieces of the first primary assembling piece231, the second primary assembling piece 232, the third primaryassembling piece 233, and the fourth primary assembling piece 234. Forexample, the two ends of the first secondary assembling piece 235 arerespectively joined to the first primary assembling piece 231 and thesecond primary assembling piece 232 that are adjacent to each other andthe two ends of the second secondary assembling piece 236 arerespectively joined the third primary assembling piece 233 and thefourth primary assembling piece 234 that are adjacent to each other, asshown in FIG. 8.

In the instant embodiment, the back frame 23 comprises seven bracingpieces 2371, 2372, 2373, 2374, 2375, 2376, and 2377. The bracing piece2371 is fixed to the fourth primary assembling piece 234; the bracingpieces 2372, 2373 are both fixed to the first secondary assembling piece235; the bracing piece 2374 is fixed to the second secondary assemblingpiece 236; the bracing piece 2375 is fixed to the second primaryassembling piece 232; and the bracing pieces 2376, 2377 are each fixed,at two ends thereof, to the first secondary assembling piece 235 and thesecond secondary assembling piece 236. In practice, the bracing piecescan be fixed to one or more of the first primary assembling piece 231,the second primary assembling piece 232, the third primary assemblingpiece 233, the fourth primary assembling piece 234, the first secondaryassembling piece 235, and the second secondary assembling piece 236. Inother embodiments, those skilled in the art may mount bracing pieces ofany other numbers to the back frame 23, such as one or more bracingpieces. Further, the bracing pieces can be releasably fixed to one ormore of the first primary assembling piece 231, the second primaryassembling piece 232, the third primary assembling piece 233, the fourthprimary assembling piece 234, the first secondary assembling piece 235,and the second secondary assembling piece 236.

The bracing pieces 2371, 2372, 2373, 2374, 2375, 2376, and 2377 may beprovided with bumps (not labeled) so that the back frame 23 may fixcomponents, such as circuit boards, with such bumps.

Molds for making the back frame 23 will be described. In the instantembodiment, the first primary assembling piece 231 and the third primaryassembling piece 233 are of the same size and shape so that they can bemade by stamping with the same mold. The second primary assembling piece232, the fourth primary assembling piece 234, the first secondaryassembling piece 235, and the second secondary assembling piece 236 areof the same size and shape so that they can be made by stamping with thesame mold, making it possible to share the mold. Thus, the back frame 23of the present invention can be made by stamping with only twosmall-sized molds, and compared to the conventional back frame 10 thatrequires a large-sized mold, the molds for making the back frame 23 ofthe present invention are simple in structure and small in size and thusthe cost of mold for the back frame 23 can be lowered. Further, comparedto the whole back frame structure of the conventional back frame 10, theback frame 23 of the present invention can significantly save materialused and thus reduce the manufacturing cost of the flat panel displaydevice 20.

Referring to FIG. 9, FIG. 9 is a schematic view showing joint sectionsof a back frame of a flat panel display device according to an eighthembodiment of the present invention. As shown in FIG. 9, in the instantembodiment, an end of the first primary assembling piece is providedwith two joint sections, and the joint sections have a structure matingan end of the second primary assembling piece so that the first primaryassembling piece can be joined to a corresponding end of the secondprimary assembling piece.

Specifically, the first primary assembling piece 231 has an end formingjoint sections 2311, 2312, and the joint sections 2311, 2312 arearranged in a spaced manner in a lengthwise direction of the firstprimary assembling piece 231. The joint sections 2311, 2312 are formedby forming recesses having a shape mating an end of the second primaryassembling piece 232 in the first primary assembling piece 231 in orderto receive the end of the second primary assembling piece 232 therein.As shown in FIG. 10, the joint sections 2311, 2312 are recesses that donot extend through opposite surfaces of the end of the first primaryassembling piece 231 and the recesses are of a rectangular shape withthe second primary assembling piece 232 being straight linear.

To assemble a large-sized back frame 23, the joint section 2311 that isclose to the very end of the first primary assembling piece 231 is firsttaken and a second primary assembling piece 232 having a correspondingwidth is selected. Afterwards, an end of the second primary assemblingpiece 232 is positioned in the recess of the joint section 2311. Andthen, means, such as screwing, fastening, or welding, is applied to joinand fix the end of the second primary assembling piece 232 to the jointsection 2311. To assemble a small-sized back frame 23, the joint section2312 that is distant from the very end of the first primary assemblingpiece 231 is first chosen and a second primary assembling piece 232having a corresponding width is selected. Afterwards, an end of thesecond primary assembling piece 232 is positioned in the recess of thejoint section 2312. And then, means, such as screwing, fastening, orwelding, is applied to join and fix the end of the second primaryassembling piece 232 to the joint section 2312. Specifically, forexample the second primary assembling piece 232 forms a protrusion at acorresponding location on a surface thereof, and the protrusion of thesecond primary assembling piece 232 is embedded in the recess the firstprimary assembling piece 231 at a corresponding location in order tojoin the first primary assembling piece 231 and the second primaryassembling piece 232, as shown in FIG. 11. Further, the second primaryassembling piece 232 may form, on one end thereof, at least twoprotrusions that are spaced in the lengthwise direction of the secondprimary assembling piece 232, such as two, three, or four protrusions.

Furthermore, the recess of the first primary assembling piece 231 can bea recess of a multi-stepped configuration and the second primaryassembling piece 232 forms, at a corresponding location, a protrusionhaving a multi-stepped configuration corresponding to the recess, asshown in FIG. 12. Further, as shown in FIG. 13, taking the joint section2311 as an example, the recess of the first primary assembling piece 231forms, in a bottom thereof, a first through hole 2313, and the secondprimary assembling piece 232 forms, at a location corresponding to thejoint section 2311, a second through hole 2321. The back frame 23further comprises a fastener 240. The fastener 240 extends through thefirst through hole 2313 and the second through hole 2321 to joint thefirst primary assembling piece 231 and the second primary assemblingpiece 232 to each other.

As shown in FIG. 14, in another embodiment of the back frame of flatpanel display device according to the present invention, the recesses ofthe joint sections 2311, 2312 of the first primary assembling piece 231are of a circular shape. Yet, in other embodiments, those skilled in theart may arrange the shape of the recesses to be other polygonalconfigurations, such as triangle.

As shown in FIG. 15, in another embodiment of the back frame of flatpanel display device according to the present invention, the jointsections 2311, 2312 are recesses that do not extend through oppositesurfaces of the first primary assembling piece 231, whereby an end ofthe second primary assembling piece 232 is movable within the jointsections 2311, 2312. For example, after the end of the second primaryassembling piece 232 is set extending beyond and joined and fixed to thejoint section 2312, the portion of extension is then trimmed off so thatthe length of the second primary assembling piece 232 that serves as aprimary assembling piece of the back frame can be adjusted.

In a practical application, the other end of the first primaryassembling piece 231 and both ends of the third primary assembling piece233 are all provided with two joint sections having a structureidentical to that of the joint sections 2311, 2312. The ends of thesecond primary assembling piece 232 and the ends of the fourth primaryassembling piece 234 may be subjected to specific designs or no designat all according to the application. For example:

(1) In a first situation, as shown in FIG. 10, the two ends of thesecond primary assembling piece 232 and the two ends of the fourthprimary assembling piece 234 are of no specific design. In other words,the ends are of the same structure as the remaining portions. Under thiscondition, in making a join with a selected joint section 2311 (2312) atone end of the first primary assembling piece 231 (the same applicableto the other end), if an attempt is made to change the width of the backframe 23, then the length of the corresponding second primary assemblingpiece 232 and fourth primary assembling piece 234 must be selectedaccordingly. Namely, if the joint section 2311 that is close to the veryend of the first primary assembling piece 231 is selected for joining,then no trimming is applied to the second primary assembling piece 232and the fourth primary assembling piece 234 or the portion that istrimmed off is short; if the joint section 2312 that is distant from thevery end of the first primary assembling piece 231 is selected forjoining, then the second primary assembling piece 232 and the fourthprimary assembling piece 234 are trimmed and the trimmed portion beinglong or short is according to the distance that the joint section isfrom the very end of the first primary assembling piece 231 being greator small; and

(2) In a second situation, it is similar to the first situation, but asshown in FIG. 11, the second primary assembling piece 232 and the fourthprimary assembling piece 234 use different protrusions to respectivelymate the first primary assembling piece 231 and the third primaryassembling piece 233 in order to realize change of width of the backframe 23; similarly, if a joint section 2312 other than the first jointsection 2311 that is close to the very end of the first primaryassembling piece 231 is selected for joining, then before or afterjoining, excessive portions of the second primary assembling piece 232and the fourth primary assembling piece 234 may be trimmed off.

This also applicable to a main frame structure 27 of the back frame 23that is formed by joining two L-shaped primary assembling pieces.

In summary, the present invention provides a back frame 23 having afirst primary assembling piece that is provided with at least two jointsections. The number of the joint section can be selected according tothe requirement of customers. In the instant embodiment, a descriptionis given to an example comprising two joint sections 2311, 2312. Thus,to prepare the molds for making the back frame 23, only two sets of moldare needed, namely one mold for a first primary assembling piece and theother mold for a second primary assembling piece. The first primaryassembling piece may be provided with a plurality of joint sections forjoining operation in order to form various sizes for the back frame 23.To assemble the back frame 23, based on the desired size of the backframe 23, the corresponding one of the joint sections is selected. Withthe joint section, the second primary assembling piece is joined to thejoint section of the first primary assembling piece and the other jointsection of the first primary assembling piece that is located outward ofthe joining location of the second primary assembling piece is trimmedoff to obtain a desired size of the back frame 23. Compared to theconventional technology that requires different back frame molds formaking different sizes of back frame 10, the back frame of the flatpanel display device 23 according to the present invention requires onlya mold for the first primary assembling piece and a mold for the secondprimary assembling piece 28 so that mold sharing among various sizes ofproduct can be realized and the molds used are of simple structures,allowing of reduction of expenditure of the molds for back frames.

The present invention also provides a mold for making a back frame offlat panel display device. The back frame mold is provided with a mainpattern for forming a primary assembling piece of the back frame and themain pattern comprises a sub-pattern that forms at least two jointsections on an end of the primary assembling piece. The primaryassembling piece comprises the previously discussed first primaryassembling piece and second primary assembling piece, corresponding tothe above mentioned main pattern; and the joint section comprises thepreviously discussed joint section of the first primary assemblingpiece, corresponding to the above mentioned sub-pattern. Repeateddescription is omitted herein.

As shown in FIG. 16, the present invention also provides a method formaking a back frame of flat panel display device. The method comprisesthe following steps:

Step 501: manufacturing at least first and second primary assemblingpieces, in which the first primary assembling piece has an end formingat least two joint sections, each of the joint sections having astructure that mates a corresponding end of the second primaryassembling piece; and

Step 502: selecting one joint section of the at least two joint sectionsaccording to a size of the back frame to join the corresponding end ofthe second primary assembling piece.

In the instant embodiment, when other joint sections are present betweenthe joining location of the second primary assembling piece and the endof the first primary assembling piece, before or after the step ofselecting one joint section of the at least two joint sections accordingto a size of the back frame to join the corresponding end of the secondprimary assembling piece, the other joint sections of the first primaryassembling piece that are located outward of the joining position of thesecond primary assembling piece are trimmed off. The first primaryassembling piece comprises the previously discussed first primaryassembling piece, and the second primary assembling piece comprises thepreviously discussed second primary assembling piece, and repeateddescription will be omitted herein.

As shown in FIG. 17, the flat panel display device 20 of the presentinvention further comprises a touch screen 29. The touch screen 29 isarranged on a light exit surface of the display panel 22 of the flatpanel display device 20. The flat panel display device 20 comprises: thebacklight system 21 and the above discussed display panel 22. Thebacklight system 21 is arranged at the back side of the display panel 22and supplies light to the display panel 22.

The backlight system 21 comprises a light source 25, a lighthomogenization mechanism 24, and a back frame 23. The back frame 23carries the light source 25 and the light homogenization mechanism 24.When the backlight system 21 is an edge lighting type, the lighthomogenization mechanism 24 is a light guide; and when the backlightsystem 21 is a direct type, the light homogenization mechanism 24 is adiffuser plate. The back frame 23 comprises at least a first primaryassembling piece and a second primary assembling piece, and the at leastone first and second primary assembling pieces constitute a main framestructure 27 of the back frame 23.

Certainly, the backlight system 21 can be of a structure of any of thepreviously discussed embodiments of backlight system.

It is noted that the flat panel display device 20 of the presentinvention can be a liquid crystal display device or a liquid crystaltelevision.

The present invention also provides a stereoscopic display device 30, asshown in FIG. 18. The stereoscopic display device 30 comprises a liquidcrystal lens grating 31, a backlight system 32, and a display panel 33.The liquid crystal lens grating 31 is arranged on a light exit surfaceof the display panel 33. The backlight system 32 can be a backlightsystem of one of the above discussed embodiments, such as the backlightsystem 32 comprising the back frame 23. The back frame 23 comprises atleast first primary assembling piece and the second primary assemblingpiece. The at least first and second primary assembling pieces form amain frame structure of the back frame. The backlight system 32 can beof a structure of any of the previously discussed embodiments ofbacklight system and repeated description will be omitted herein.

The present invention also provides a plasma display device 40, as shownin FIG. 19. The plasma display device 40 comprises a plasma displaypanel 41 and a back frame 42. The back frame 42 is arranged at a backside of the display panel 41. The back frame 42 can be the back frame ofany of the previously discussed embodiments and repeated descriptionwill be omitted herein.

With the above described manner, the flat panel display device, thestereoscopic display device, and the plasma display device of thepresent invention have a back frame mold that is of a simple structure,reduce the expenditure of the back frame mold, save the material for theback frame, and thus lower down the cost of flat panel display device.

The present invention further provides a mounting means that isapplicable to the bracing pieces and the assembling pieces of each ofthe above described embodiments, whereby with pawl mating engagement,fast mounting and removal of the bracing pieces can be realized.

Specifically, as shown in FIG. 20, a bracing piece 50 comprises pawls51, 52 extending downwards. An assembling piece 61 forms engagementsites 611 for receiving the pawl 51 and an assembling piece 62 forms anengagement site 621 for receiving the pawl 52. In mounting the bracingpiece 50, the pawl 51 and the pawl 52 are respectively inserted into theengagement site 611 and the engagement site 621 to have the pawls 51engage the engagement site 611 and also to have the pawl 51 engage theengagement site 621, whereby opposite ends of the bracing piece 50 arerespectively fixed to the assembling piece 61 and the assembling piece62 to realize fast mounting of the bracing piece 50.

Similarly, when it is attempted to remove the bracing piece 50 from theassembling pieces 61, 62, the pawls 51, 52 are deflected inward to causedeformations of the pawls 51, 52 for disengaging from the engagementsites 611, 621 thereby realizing fast removal of the bracing piece 50.

It is noted that in the instant embodiment, the bracing piece 50 can beintegrally formed through stamping with a mold.

As shown in FIG. 21, in another embodiment of the present invention, abracing piece 70 forms inverted U-shaped pawls 71, 72. An assemblingpiece 81 forms an engagement site 811 for receiving the pawl 71 and anassembling piece 82 forms an engagement site 821 for receiving the pawl72. In mounting the bracing piece 70, the pawl 71 and the pawl 72 arerespectively inserted into the engagement site 811 and the engagementsite 821 to have the pawl 71 engage the engagement site 811 and also tohave the pawl 72 engage the engagement site 821, whereby opposite endsof the bracing piece 70 are respectively fixed to the assembling piece81 and the assembling piece 82 to realize fast mounting of the bracingpiece 70.

Similarly, when it is attempted to remove the bracing piece 70 from theassembling pieces 81, 82, the pawls 71, 72 are deflected inward to causedeformations of the pawls 71, 72 for disengaging from the engagementsites 811, 821 thereby realizing fast removal of the bracing piece 70.

It is noted that in the instant embodiment, the bracing piece 70 can beformed by bending a metal material.

Thus, with the above discussed manners, the present invention provides aback frame and a backlight system of a flat panel display device thatform a back frame through joining assembling pieces so that thestructure of a mold for back frame is simple, the expenditure for theback frame mold is reduced, the material for the back frame is saved,and the cost of flat panel display device is lowered down. Further,through the pawl mating arrangement of the bracing piece and theassembling piece of the back frame, the bracing piece of the back framerealizes fast mounting and removal.

Embodiments of the present invention have been described, but are notintending to impose any undue constraint to the appended claims of thepresent invention. Any modification of equivalent structure orequivalent process made according to the disclosure and drawings of thepresent invention, or any application thereof, directly or indirectly,to other related fields of technique, is considered encompassed in thescope of protection defined by the claims of the present invention.

What is claimed is:
 1. A back frame of a flat panel display device,wherein the back frame comprises at least two assembling pieces, the atleast two assembling pieces being joined to form the back frame, theback frame further comprising a bracing piece, the bracing piece beingset in pawl mating engagement with the assembling pieces; and whereinthe back frame comprises at least two primary assembling pieces, the atleast two primary assembling pieces being joined to form a main framestructure of the back frame, the at least two primary assembling piecescomprising a first primary assembling piece and a second primaryassembling piece, the first primary assembling piece having an endconnectable to an end of the second primary assembling piece forjointing the first and second primary assembling pieces, the end of thefirst primary assembling piece forming at least two joint sections, eachof the joint sections having a structure mating the end of the secondprimary assembling piece, the end of second primary assembling piecebeing switchably jointed to one of the at least two joint sections ofthe first primary assembling piece by selectively using one of the jointsections so that the second primary assembling piece is connected to thefirst primary assembling piece in a position-adjustable manner.
 2. Theback frame as claimed in claim 1, wherein the bracing piece forms pawlsthereon and the assembling pieces form engagement sites for receivingthe pawls.
 3. The back frame as claimed in Claim 1, wherein: the atleast two joint sections are arranged to space from each other in alengthwise direction of the first primary assembling piece.
 4. The backframe as claimed in claim 3, wherein: the joint sections compriserecesses formed in a surface of the first primary assembling piece andhaving a shape corresponding to the end of the second primary assemblingpiece for receiving the end of the second primary assembling piece. 5.The back frame as claimed in claim 3, wherein: the joint sectionscomprise recesses formed in a surface of the first primary assemblingpiece, the second primary assembling piece having a surface formingprotrusions at corresponding positions, the protrusions being receivablein the recesses to join the first primary assembling piece and thesecond primary assembling piece to each other.
 6. The back frame asclaimed in claim 5, wherein: the second primary assembling piece has anend having a surface forming at least two protrusions that are arrangedto space from each other in a lengthwise direction of the second primaryassembling piece.
 7. The back frame as claimed in claim 6, wherein: therecesses comprise polygonal recesses and the protrusions are shaped ascorresponding polygonal protrusions.
 8. The back frame as claimed inclaim 6, wherein: the recess of the first primary assembling piece formsin a bottom thereof a first through hole, the second primary assemblingpiece forming in a corresponding location a second through hole, theback frame comprising a fastener, the fastener extending through thefirst through hole and the second through hole to join the first primaryassembling piece and the second primary assembling piece to each other.9. A backlight system, wherein: the backlight system comprises a lightsource, a light homogenization mechanism, and a back frame; and the backframe carries the light source and the light homogenization mechanism,the back frame being a back frame claimed in claim
 1. 10. A back frameof a flat panel display device, wherein the back frame comprises atleast two assembling pieces, the at least two assembling pieces beingjoined to form the back frame, the back frame further comprising abracing piece, the bracing piece being set in pawl mating engagementwith the assembling pieces; wherein the back frame comprises at leasttwo primary assembling pieces, the at least two primary assemblingpieces being joined to form a main frame structure of the back frame,the at least two primary assembling pieces comprising a first primaryassembling piece and a second primary assembling piece, the firstprimary assembling piece having an end forming at least two jointsections, each of the joint sections having a structure mating an end ofthe second primary assembling piece, the first primary assembling pieceusing one of the joint sections to join the corresponding end of thesecond primary assembling piece; wherein the at least two joint sectionsare arranged to space from each other in a lengthwise direction of thefirst primary assembling piece; wherein the joint sections compriserecesses formed in a surface of the first primary assembling piece, thesecond primary assembling piece having a surface forming protrusions atcorresponding positions, the protrusions being receivable in therecesses to join the first primary assembling piece and the secondprimary assembling piece to each other; and wherein the second primaryassembling piece has an end having a surface forming at least twoprotrusions that are arranged to space from each other in a lengthwisedirection of the second primary assembling piece.
 11. The back frame asclaimed in claim 10, wherein the recesses comprise polygonal recessesand the protrusions are shaped as corresponding polygonal protrusions.12. The back frame as claimed in claim 10, wherein the recess of thefirst primary assembling piece forms in a bottom thereof a first throughhole, the second primary assembling piece forming in a correspondinglocation a second through hole, the back frame comprising a fastener,the fastener extending through the first through hole and the secondthrough hole to join the first primary assembling piece and the secondprimary assembling piece to each other.